Pole structure



Dec. 2091932. I T. J. CRAWFORD 1,391,620 Q POLE STRUCTURE I Filed Sept. 50.- 1929 2 Sheets-Shet 1 MAX FIEJZ dew/M Dec. 20, 1932. T, CRAWFORD v I 1,891,620

POLE STRUCTURE Filed Sept. 50, 1929 2 Sheets-Sheet 2 Patented Dec. 20, 1932 THOMAS J; CRAWFORD, or younes'ro'wn, OHIO I POLE STRUCTURE Application filed September 30, 1929. Serial No. 396,158; 2

This invention relates to hollow metal members and more particularly to tubular poles such as are used to support electric conductors, pipes, wires, cables and the like.

5 Heretofore, one form of metal pole, which has been used for this purpose has been made by inserting one end of a piece of pipe into I the end of a larger piece, and then pressing the overlapping portions together with dies.

This necessitates the use of low carbon metal and hence requires an objectionable weight in order to obtain a pole of the desired strength.

The method is also objectionable as the amount of metal, which had to be used, made 1 the cost excessive.

Another form of pole has been made from seamless tubing of different diameters with the end of one section reduced to form a neck into which the end of the adjacent section has been pressed, but seamless tubing is objectionable because of the excessive cost. A more important consideration however, is the fact that the reduction in diameter increases the deflection, notwithstanding the fact that the same fibre stress is maintained throughout.

It is well known that deflection in trolley wire supports causes breakage of insulators, particularly when a snow and ice load is added to the wires. Hence, to avoid such deflection, it has been necessary to increase the wall thickness and thereby to add materially to the weight and cost of manufacture. Again, there is an overlapping of metal at the joint which adds to the weight and re duces the efliciency. Still another form of pole which has heretofore been used, has been made from a tube which is drawn downwardly at predetermined intervals so as to main- 40 tain the same wall thickness but varying the diameter. This pole is open to the same objection as to deflection, and is too expensive to manufacture.

The principal objects of the present invention therefore, are to make a pole which will require a minimum of material in order to obtain the necessary strength, and also to provide an economical method of manufacturing poles of any desired form.

I accomplish these objects by providing a tudinal cross-sectional views of modifications of my invention;

pole wherein the sections are butt welded en d to end. One form ofthe invention compris i the utilization of blanks which are butt welded at the ends tor form a composite blank, which is then formed to make a hollow memher having ahorizontally extending seam.

T hefwelding of the longitudinal and transverse joints may be accomplished by'the usual butt welding and pipe welding machines. Otherforms of myinvention are illustrated} in the drawings andare hereafter described,

while the essential features are pointed'out in the claims. V I

In the drawings, Fig. 1 is a plan view show ing the stock usedin one form ofpole'manu-, ,f facture embodying my invention; Fig. 2 is a" cross-sectional view of the material shown in Fig. 1; Fig. 3 is a planview showing the blanks butt-welded together; Fig.4 is fa cross-sectional'view of'Fig. 3; Fig. 5 shows,v T the welded blanks formedintoa tube; Fig) his a cross-section takenalong theline 6"'6 in Fig. 5 Fig. 7 is a view of the Welded pole; Fig. 8, is a cross-section taken along the line 88 of Fig. 7; and Figs. 9and- 10 are longi-,,

5 Referring more particularly to the'drawings in Figs. 1 and 2', the pieces of raw stock, which may be used in making a pole, are iii- ,80 dicated by 21, 22 and 23. These pieces, as? shown, are all of the same width so that they can be formed into a tubeof uniform di- 7 ameter, but they are of progressively decreasing thickness, the bottom section 21 being heavier than the intermediate section 22, which in turn, is heavierthan the top. Section 23. While I have shownthree sections,

it is obvious that two oranynumbergreater than two sections could be used. The length, thickness andnumber ofsections arefdeter mined by individual design requirements.

The next step in the manufacture of the {pole maybe to weld the endsof the bottom, intermediate and'top sections together, as'at 24 and 25 3 and 4:). Thes a welds" y be made y any convenient. process such as electric resistance welding. The sections may be jointed together so as to produce av blank having. one planesurface which forms the outside of the tube or pole, the other surface being formed in aseries of steps to allow for the variations in thickness of the sections.

The blank may then be hot or cold rolled or pressed into a cylindrical or tubular shape, as shown in Figs. and 6, leaving an open seam 26. The edges of the seam may then be welded together as at 27 (Figs. 7 and 8) by" 1 resistance, arc, gas or other welding process.

The completed tube is then ready for any finishing operations which may be necessary, 7

such as rolling or pressing the top portion 23 into a squared shape, in order to facilitate attachment of fittings of equipment. While only a square cross-section is described, an elliptical, polygonal or any other desired shape could be employed.

A pole similarto that shown may also be manufactured from sections of standard tubing. To this end, pieces having the proper uniform external diameter, and varying internal diameters may be-welded together at their ends by any convenient method.

I In Fig. 8, I show a pole having a uniform internal diameter and a varying external diameter. A pole of this type may be manufactured by forming the blank shown in Figs. 3 and 4 over a mandrel and into a tube havinga uniform internal'diameter. The longitudinal seam may then be welded by any convenient method, such as are or gas welding, and the pole finished for fittings in any desired manner. A pole of this type may also be manufactured by butt welding the ends of pieces of tubing of the desired dimensions.

In Fig. 10, I show a form of pole which may be easily and economically manufactured by welding sections of standard tubing together at their ends. In the modification shown in Fig. 10, the averages of the internal and external diameters of the sections 30, 31 and 32 may be substantially equal, and the thickness of the walls may be progressively varied. The sections may be butt-welded together as at 33 and 34.

It is to be understood that the upper section of poles made according to any of the above modifications may be deformed in order to facilitate attachment of fittings. Furthermore, if desired, the entire pole may be deformed to obtain various ornamental shapes.

. From the foregoing description of the preferred forms of my invention, it will be seen that I have provided a pole which may be easily and economically manufactured, in which great strength is secured with a minimum of material and which may be adapted to a variety of uses.

' I claim:

1. A hollow metal one piece cantilever member comprising successivesectionsof difrent' th c ded oge er an 85 having internal and external dimensions, the

signature.

THOMAS J. CRAWFORD. 

